Retinal Imaging In Early Alzheimer'S Disease

Changes in the brain that lead to Alzheimer's disease are thought to start decades before cognitive symptoms emerge. If biomarkers for these early stages could be identified, it would contribute to a more accurate estimation of an individual's risk of developing disease and enable the monitoring of high-risk (presymptomatic) persons as well as providing the means for assessing the efficacy of new interventions. The retina links to the visual processing and cognitive centers of the brain, but it is also an extension of the brain sharing embryological origins as well as a blood supply and nerve tissue. It therefore has huge potential as a site for biomarker investigation through easy, noninvasive imaging and computational image analysis to reveal valuable information about microvascular health, deposition, and neurodegenerative damage. Capturing reliable longitudinal data pertaining to the onset of Alzheimer's disease is a key target, but a high degree of standardization is necessary if the potential of the retina is to be fully realized. Our goal is to provide the reader with guidelines on how to execute robust retinal imaging and analysis for neuroretinal biomarker discovery and to highlight advantages and limitations of the techniques.